Hybrid stepping motor

A hybrid stepping motor according to the present invention has coils wound on stator yokes arranged on a fixed shaft or coils arranged on the inner peripheral surface of stator yokes. For this reason, the coils can be easily formed, a coil mounting density higher than that by a conventional technique can be obtained, and cost reduction can be obtained. An auxiliary magnetic plate and an auxiliary magnet are arranged on both the sides of a stator yoke member to form magnetic circuits at both the ends of the stator yoke member. Therefore, motors having various numbers of phases can be obtained, and a core are partially or entirely constituted by a non-layered structure, thereby improving torque/current characteristics.

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Claims

1. A hybrid stepping motor comprising: a pair of bearings arranged to be spaced apart from a fixed shaft; a rotor case rotatably arranged through said bearings; an annular rotor yoke arranged on an inner surface of said rotor case and having a plurality of rotor teeth; first and second stator yokes parallelly arranged on said fixed shaft in an axial direction and separated by a magnet plate; a plurality of stator teeth formed on outer peripheral surfaces of said stator yokes; first and second coil receiving grooves respectively formed at an axially central position at an outer periphery of each of said stator yokes; and first and second coils respectively arranged in said first and second coil receiving grooves, wherein said stator yokes are designed to have different polarities, and at least on of said annular rotor yoke and said stator yokes has a portion constituted by a non-layered core.

2. A hybrid stepping motor comprising: a pair of bearings arranged at both the ends of a casing; a rotating shaft rotatably arranged through said bearings; first and second annular stator yokes parallelly arranged on an inner surface of said casing in an axial direction and separated by an annular magnet plate; a plurality of stator teeth formed on inner surfaces of said annular stator yokes; first and second coil receiving grooves formed at an axillary central position at an inner periphery of each of said stator yokes; first and second coils respectively arranged in said coil receiving grooves, a rotor yoke arranged on said rotating shaft and located in correspondence with said stator yokes; and a plurality of rotor teeth formed on an outer peripheral surface of said rotor yoke, wherein at least one of said annular stator yokes and said rotor yoke has a portion constituted by a non-layered core.

3. A hybrid stepping motor comprising: a pair of bearings arranged to be spaced apart from a fixed shaft; a rotor case rotatably arranged through said bearings; an annular rotor yoke arranged on an inner surface of said rotor case and having a plurality of rotor teeth; a cylindrical magnet member arranged on an outer peripheral surface of said fixed shaft; a pair of first and second annular stator yokes arranged to be fitted on an outer peripheral surface of said cylindrical magnet member, a plurality of stator teeth formed on outer peripheral surfaces of said stator yokes; first and second coil receiving grooves formed at an axially central position at an outer periphery of each of said annular stator yokes in an axial direction; and first and second coils respectively arranged in said coil receiving grooves, wherein said annular stator yokes are designed to have different polarities, and at least one of said annular rotor yoke and said annular stator yokes has a portion constituted by a non-layered core.

4. A hybrid stepping motor according to claim 3, characterized in that a void is formed between said annular stator yokes.

5. A hybrid stepping motor comprising: a bearing arranged on a fixed shaft; a cylindrical rotor rotatably arranged through said bearing; a plurality of rotor teeth formed on inner and outer peripheral surfaces of said cylindrical rotor; first and second inner stator yokes and first and second outer stator yokes parallelly arranged on said fixed shaft in an axial direction and separated by a magnet plate; a plurality of stator yoke teeth formed on said stator yokes; a first to fourth coil receiving grooves formed at axially central positions of said inner and outer stator yokes toward said cylindrical rotor; and first to fourth coils which are respectively arranged in said coil receiving grooves and bobbin-wound, wherein said stator yokes are designed to have different polarities, said coils arranged to interpose said cylindrical rotor, and at least one of said cylindrical rotor and said stator yokes has a portion constituted by a non-layered core.

6. A hybrid stepping motor according to claim 5, wherein said magnet plate is constituted by first and second magnets respectively arranged between said inner stator yokes and between said outer stator yokes.

7. A hybrid stepping motor according to claim 5, characterized in that said magnet plate is constituted by first and second magnets arranged between said inner stator yokes and said fixed shaft and between said outer stator yokes and an outer wall of said fixed shaft, and said magnets oppose each other through said cylindrical rotor.

8. A hybrid stepping motor which is of an outer-rotor type, comprising: a pair of bearings arranged to be spaced apart from a fixed shaft; a rotor case rotatably arranged through said bearings; an annular rotor yoke arranged in said rotor case and having a plurality of rotor teeth; a stator yoke member constituted by n stator yokes parallelly arranged on said fixed shaft in an axial direction and separated by a magnet plate; a plurality of stator teeth formed on an outer peripheral surface of said stator yokes; n coil receiving grooves respectively formed at an axially central position at an outer periphery of each of said stator yokes; n coils respectively arranged in said coil receiving grooves; and a pair of auxiliary magnetic plates arranged at each of the ends of said stator yoke member on said fixed shaft, each said auxiliary magnetic plate being separated from said stator yokes by an auxiliary magnet plate; wherein said stator yokes form polarities which are different from each other, a magnetic flux generated by said auxiliary magnet plates passes through said auxiliary magnetic plates, and at least one of said annular rotor yoke and said stator yokes has a portion constituted by a non-layered core.

9. A hybrid stepping motor according to claim 8, characterized in that said stator yokes comprise three stator yokes, and are designed to be three-phase-driven.

10. A hybrid stepping motor according to claim 8, characterized in that said stator yokes comprise two stator yokes, and are designed to be two-phase-driven.

11. A hybrid stepping motor which is of an inner-rotor type, comprising: a pair of bearings arranged at both the ends of a casing; a rotating shaft rotatably arranged through said bearings; a stator yoke member constituted by n annular stator yokes parallelly arranged on an inner surface of said casing in an axial direction and separated by an annular magnet plate; a plurality of stator teeth formed on an inner peripheral surface of said annular stator yokes; a pair of auxiliary magnetic-plates positioned at both the ends of said stator yoke member each said auxiliary magnet plate being separated from said stator yoke by an auxiliary magnet plate; n coil receiving grooves respectively formed at an axially central position at an inner periphery of each said annular stator yokes; n coils respectively arranged in said coil receiving grooves; a rotor yoke arranged on said rotating shaft and located in correspondence with said stator yokes; and a plurality of rotor teeth arranged on an outer peripheral surface of said rotor yoke, wherein a magnetic flux generated by said auxiliary magnet plates passes through said auxiliary magnetic plates, and at least one of said annular stator yokes and said rotor yoke has a potion constituted by a non-layered core.

12. A hybrid stepping motor according to claim 11, characterized in that said annular stator yokes comprise three annular stator yokes, and are designed to be three-phase-driven.

13. A hybrid stepping motor according to claim 11, characterized in that said annular stator yokes comprise two annular stator yokes, and are designed to be two-phase-driven.

14. A hybrid stepping motor which is of an outer-rotor type according to claim 8, wherein said stator yoke member comprises a plurality of stator yoke members arranged through said magnet plate, and the number of said stator yoke members is N.

15. A hybrid stepping motor which is of an outer-rotor type according to claim 9, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet plate, and the number of said stator yoke members is N.

16. A hybrid stepping motor which is of an outer-rotor type according to claim 10, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet plate, and the number of said stator yoke members is N.

17. A hybrid stepping motor which is of an inner-rotor type according to claim 11, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet plate, and the number of said stator yoke members is N.

18. A hybrid stepping motor which is of an inner-rotor type according to claim 12, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet plate, and the number of said stator yoke members is N.

19. A hybrid stepping motor which is of an inner-rotor type according to claim 13, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet plate, and the number of said stator yoke members is N.

20. A hybrid stepping motor which is of an outer-rotor type, comprising: a pair of bearings arranged to be spaced apart from a fixed shaft; a rotor case rotatably arranged through said bearings; an annular rotor yoke arranged in said rotor case and having a plurality of rotor teeth; a stator yoke member constituted by n stator yokes parallelly arranged on said fixed shaft in an axial direction and separated from said fixed shaft by a cylindrical magnet member; a plurality of stator teeth formed on an outer peripheral surface of said stator yokes; n coil receiving grooves formed at an axially central position at an outer periphery of each of said stator yokes; n coils respectively arranged in said coil receiving grooves; and a pair of auxiliary magnetic plates arranged at each of the ends of said stator yoke member on said fixed shaft and separating said fixed shaft from a respective end of said stator yoke member; wherein said stator yokes alternately form polarities which are different from each other, a magnetic flux generated by said auxiliary magnet plates passes through said auxiliary magnetic plates, and at least one of said annular rotor yokes and said stator yokes has a portion constituted by a non-layered core.

21. A hybrid stepping motor according to claim 20, characterized in that said stator yokes comprise three stator yokes, and are designed to be three-phase-driven.

22. A hybrid stepping motor according to claim 20, characterized in that said stator yokes comprise two stator yokes, and are designed to be two-phase-driven.

23. A hybrid stepping motor which is of an inner-rotor type, comprising: a pair of bearings arranged at both the ends of a casing; a rotating shaft rotatably arranged through said bearings; a stator yoke member constituted by n annular stator yokes parallelly arranged on an inner surface of said casing in an axial direction and separated by an annular cylindrical member; a plurality of stator teeth formed on an inner peripheral surface of said annular stator yokes; a respective auxiliary cylindrical magnet positioned at each of the ends of said stator yoke member and separating a respective one of the ends of said casing from said stator yoke member; n coil receiving grooves respectively formed at an axially central position at an inner periphery of each of said annular stator yokes; n coils respectively arranged in said coil receiving grooves; a rotor yoke arranged on said rotating shaft and located in correspondence with said stator yokes; and a plurality of rotor teeth arranged on an outer peripheral surface of said rotor yoke, wherein a magnetic flux generated by said auxiliary cylindrical magnet members passes through said auxiliary cylindrical magnet members, and at least one of said annular stator yokes and said rotor yoke has a portion constituted by a non-layered core.

24. A hybrid stepping motor according to claim 23, characterized in that said annular stator yokes comprise three annular stator yokes, and are designed to be three-phase-driven.

25. A hybrid stepping motor according to claim 23, characterized in that said annular stator yokes comprise two annular stator yokes, and are designed to be two-phase-driven.

26. A hybrid stepping motor which is of an outer-rotor type according to claim 20, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet cylindrical member, and the number of said stator yoke members is N.

27. A hybrid stepping motor which is of an outer-rotor type according to claim 21, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet cylindrical member, and the number of said stator yoke members is N.

28. A hybrid stepping motor which is of an outer-rotor type according to claim 22, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet cylindrical member, and the number of said stator yoke members is N.

29. A hybrid stepping motor which is of an inner-rotor type according to claim 23, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet cylindrical member, and the number of said stator yoke members is N.

30. A hybrid stepping motor which is of an inner-rotor type according to claim 24, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet cylindrical member, and the number of said stator yoke members is N.

31. A hybrid stepping motor which is of an inner-rotor type according to claim 25, characterized in that said stator yoke member comprises a plurality of stator yoke members arranged through said magnet cylindrical member, and the number of said stator yoke members is N.

Referenced Cited
U.S. Patent Documents
3671841 June 1972 Hoffmann
4127802 November 28, 1978 Johnson
4501980 February 26, 1985 Welburn
4952859 August 28, 1990 Torisawa et al.
4963775 October 16, 1990 Mori
5289066 February 22, 1994 Clark
5506458 April 9, 1996 Pace et al.
Patent History
Patent number: 5834865
Type: Grant
Filed: Sep 26, 1996
Date of Patent: Nov 10, 1998
Assignee: Tamagawa Seiki Kabushiki Kaisha (Nagano-ken)
Inventor: Tsuneo Sugiura (Nagano-ken)
Primary Examiner: Steven L. Stephan
Assistant Examiner: Timothy A. Williams
Law Firm: Sughrue, Mion, Zinn, Macpeak & Seas, PLLC
Application Number: 8/722,843
Classifications
Current U.S. Class: 310/49R; Inbuilt Or Incorporated Unit (310/67R); Toroidal Coil (310/164); Plural Units, Structurally United (310/112); Plural Rotary Elements (310/114)
International Classification: H02K 3700;